Conventional EDM power feed systems, various types of which have been in practical use, commonly employ a discharge pulsing means which is customarily a bank of transistors or other electronic switching elements connected between a DC source and the machining gap. Such switching means is, according to a conventional EDM principles, designed to chop the continuous DC output and to be periodically or aperiodically switched by an oscillator which provides a succession of pulsing signals corresponding in time parameters, i.e. on-time, off-time and frequency, precisely to electrical discharges to be created across the machining gap. When the switching means is turned on and off with each individual pulsing signal, the continuous DC output of the source is chopped or "pulsed", thereby developing each individual localized and discrete machining discharge or energy pulse through the gap. Thus, a succession of machining electrical discharges are governed and exactly controlled by a corresponding succession of pulsing signals preset in the oscillator. Such a conventional design of pulsing circuitry is based on the common recognition in the art that a well-defined, discrete and quantumized power is preferred to achieve discharge stock removal. If the continuous power is not pulsed, it has commonly been believed that there would only result an arc discharge which tends to thermally damage the tool electrode or workpiece or both. It has also been commonly recognized to be essential to minimize a stray capacitance in the gap discharge circuit since it would causse a serious distortion of the discharge waveform and cause it to deviate considerably from the rectangular waveform of the pulsing signals.